This invention relates generally to an electrophoretic apparatus, and more particularly to an apparatus for applying a given amount of sample liquid such as blood serum sample onto a sampl bearing film which has been previously wetted with a buffer solution such as Veronal-Veronal soda solution.
In a known electrophoretic apparatus shown in FIG. 1 a sample bearing film 1 is wetted with a buffer solution 2 in a wetting section A by transporting the film 1 between a pair of rollers 3 made of sponge material, one of which is dipped in the buffer solution 2. Such a wetting section A is disclosed in U.S. Pat. No. 4,173,943. Then the wetted sample bearing film 1 is introduced in a sample applying section B which is isolated from an ambient atmosphere by a housing 4. In this section B are arranged a plurality of applicator chips 5 each of which holds at its front edge a given amount of sample liquid. Then the chips 5 are moved downward by means of a cam 6 and a motor 7 and are made in contact with the sample bearing film 1 to apply simultaneously a plurality of sample liquids onto the film 1. Usually a time duration from an instance when the sample bearing film 1 is wetted with the buffer solution 2 in the wetting section A to an instance at which the sample liquids are applied to the film 1, and a time period during which the applicator chips 5 are made in contact with the film 1 are fixedly predetermined to constant time periods. Therefore, even if the sample bearing film 1 has not a constant wet condition and thus, an absorbing ability of the film 1 varries due to a secular variation of the wet condition of the wetting rollers 3 and a variation of an ambient atmosphere, particularly humidity, the sample liquids are applied to the sample bearing film 1 always at a fixedly predetermined time instance. This results in that the sample liquids are not applied to the film 1 in a correct manner and thus, fractioned images might be affected seriously and accurate data could not be obtained. That is to say, when the sample bearing film 1 is too wetted, the sample liquids are liable to spread widely along the surface of film. In an extreme case adjacent samples might be contaminated with each other. When the film 1 is too dried, the sample liquids are not applied uniformly throughout the surface of film 1.
In the electrophoresis the wetness of the sample bearing film during the electrophoretic process is very important for obtaining accurately fractioned image. However, in the known electrohoretic apparatus the wetness of the sample bearing film under the electrophoretic process is not made constant.